Possible duplicates in swagger.yml

[pierwill]

When looking through the swagger summaries, I noticed a few duplicates.

$ cd go/src/github.com/influxdata/influxdb/http/
$ cat swagger.yml | grep "summary:" | uniq -d
      summary: Update a check
      summary: Update a notification rule
      summary: Update a notification endpoint

E.g., here and here.

If these are in fact different, let's update the summaries. Otherwise some cleanup might be in order.